Astragaloside â £ negatively regulates Gpr97-TPL2 signaling to protect against hyperhomocysteine-exacerbated sepsis associated acute kidney injury.

BACKGROUND: Hyperhomocysteine (HHcy) plays an important role in promoting inflammation and cell death of tubular epithelial cells. However, the role of HHcy and Astragaloside IV (AS-IV) in sepsis associated acute kidney injury (S-AKI) remain unclear. PURPOSE: A significant aspect of this study aimed to elucidate the effect of AS-Ⅳ treatment on HHcy-exacerbated S-AKI and reveal its potential mechanism. METHODS: Male C57BL/6 J mice fed with specific diet containing 2% methionine were established as in vivo models, and AS-Ⅳ was orally administrated continuously for 3 weeks, and then LPS (10 mg·kg-1 bodyweight) was given by a single intraperitoneal injection. The renal morphological changes were evaluated by HE and PAS staining. RNA-sequencing analysis was applied to select key signaling. The NRK-52E cells exposed to Hcy or combined with LPS were used as in vitro models. The mRNA and protein expression levels of Gpr97-TPL2 signaling were examined by qRT-PCR and western blotting assays. RESULTS: In vivo, HHcy mice developed more severe renal injury and prevalent tubular inflammation after LPS injection. In vitro, the levels of NGAL, Gpr97 and TPL2 were significantly increased in NRK-52E cells induced by Hcy (1.6 mM) or in combination with LPS. Notably, the effects of Hcy on TPL2 signaling was abolished by transfecting TPL2 siRNA or treating TPL2 inhibitor, without alterations in Gpr97. However, the enhancement of Gpr97-TPL2 signaling induced by Hcy was counteracted by Gpr97 siRNA. Subsequently, our findings demonstrated that AS-Ⅳ treatment can improve renal function in HHcy-exacerbated S-AKI mice. Mechanistically, AS-Ⅳ alleviated renal tubular damage characterized by abnormal increases in KIM-1, NGAL, TPL2, Gpr97, Sema3A and TNF-α, and decreases in survivin in vivo and in vitro mainly through suppressing the activation of Gpr97-TPL2 signaling. CONCLUSION: The present study suggested that HHcy-exacerbated S-AKI was mediated mechanically by activation of Gpr97-TPL2 signaling for the first time. Furthermore, our research also illustrated that AS-Ⅳ protected against HHcy-exacerbated S-AKI by attenuating renal tubular epithelial cells damage through negatively regulating Gpr97-TPL2 signaling, proposing a natural product treatment strategy for HHcy-exacerbated S-AKI.

Study of hispidulin in the treatment of uric acid nephropathy based on NF-κB signaling pathway.

Uric acid nephropathy (UAN) is caused by purine metabolism disorders. UAN rat models were established in SD rats. The modeling rats received different doses of hispidulin (10, 20, 50 mg/mL). Febuxostat was applied as the positive drug. Serum creatinine, uric acid (UA), and cystatin-C (cys-C), neutrophil gelatinase-associated lipocalin (NGAL), IL-1ß, IL-8, TNF-α, and IL-6 in rats were detected. HE staining was done to assess kidney injury. UAN rats possessed prominent levels of serum creatinine, UA, cys-C, and NGAL, which all reduced after hispidulin treatment in a dose-dependent manner. HE staining determined the improvement of kidney injury after treatment, which was comparable to the efficacy of febuxostat. Hispidulin inhibited the release of IL-1ß, IL-8, TNF-α, and IL-6 in UAN rats. Hispidulin enhanced autophagy in UAN rats, presenting as ascending LC3II/I ratio and downregulated P62. The increasing trend of inflammasome-related proteins of NLRP3 and Caspase-1 was changeovered by hispidulin. The activation of NF-kB signaling was intercepted by hispidulin in UAN rats. Hispidulin can effectively improve renal function injury caused by UAN in rats. The mechanism may be related to the inhibition of inflammatory response induced by autophagy and activation of NF-κB pathway.

Linalool prevents kidney damage by inhibiting rifampicin-induced oxidative stress and apoptosis.

Today, kidney diseases are increasing day by day and life quality is decreasing. In hospitalized patients of all ages, acute kidney injury (AKI) is commonly observed and associated with high rates of morbidity and mortality. Rifampicin (RF) or rifampin is an antibiotic drug from the rifamycin group with a bactericidal effect. RF causes acute kidney injury, often anemia, thrombocytopenia, liver damage and side effect such as cell death. RF causes tissue damage by means of oxidative stress and apoptosis. Thus, in this study, it was examined whether linalool (LN) which had antinociceptive, antimicrobial, antioxidant and anti-inflammatory effects, was beneficial for kidney damage in order to eliminate the side effects of RF. NGAL mRNA, creatinine (Cr), blood urea nitrogen (BUN), Caspase 9 (CAS-9) and nuclear factor-κB (NF-κB) levels increased in the group treated with RF compared to the control group, while the levels of albumin, uric acid and total protein were decreased in the RF-treated group. NGAL mRNA, BUN, Cr, CAS-9 and NF-κB levels decreased significantly in RF+LN administered rats, while it was observed that there was an increase in the levels of albumin, uric acid and total protein. From the results obtained, it was observed that LN was determined to be very effective in preventing tissue damage in kidneys caused by oxidative stress by RF.

Lipocalin-2 promotes acute lung inflammation and oxidative stress by enhancing macrophage iron accumulation.

Lipocalin-2 (LCN2) is an acute-phase protein that regulates inflammatory responses to bacteria or lipopolysaccharide (LPS). Although the bacteriostatic role of LCN2 is well studied, the function of LCN2 in acute lung damage remains unclear. Here, LCN2 knockout (KO) mice were used to investigate the role of LCN2 in LPS-treated mice with or without recombinant LCN2 (rLCN2). In addition, we employed patients with pneumonia. RAW264.7 cells were given LCN2 inhibition or rLCN2 with or without iron chelator deferiprone. LCN2 KO mice had a higher survival rate than wild-type (WT) mice after LPS treatment. In addition to elevated LCN2 levels in serum and bronchoalveolar lavage fluid (BALF), LPS treatment also increased LCN2 protein in alveolar macrophage lysates of BALF. LCN2 deletion attenuated neutrophil and macrophage infiltration in the lungs of LPS-treated mice as well as serum and BALF interleukin-6 (IL-6). Circulating proinflammatory cytokines and LCN2-positive macrophages were prominently increased in the BALF of pneumonia patients. In addition to increase of iron-stained macrophages in pneumonia patients, increased iron-stained macrophages and oxidative stress in LPS-treated mice were inhibited by LCN2 deletion. In contrast, rLCN2 pretreatment aggravated lung inflammation and oxidative stress in LPS-treated WT mice and then resulted in higher mortality. In RAW264.7 cells, exogenous LCN2 treatment also increased inflammation and oxidative stress, whereas LCN2 knockdown markedly diminished these effects. Furthermore, deferiprone inhibited inflammation, oxidative stress, and phagocytosis in RAW264.7 cells with high LCN2 levels, as well as LPS-induced acute lung injury in WT and LCN2 KO mice. Thus, these findings suggest that LCN2 plays a key role in inflammation and oxidative stress following acute lung injury and that LCN2 is a potential therapeutic target for pneumonia or acute lung injury.

Assessing acute colitis induced by dextran sulfate sodium in rats and its impact on gastrointestinal fluids.

Dextran sulfate sodium (DSS) is commonly used to induce colitis in rats. While the DSS-induced colitis rat model can be used to test new oral drug formulations for the treatment of inflammatory bowel disease, the effect of the DSS treatment on the gastrointestinal tract has not been thoroughly characterized. Additionally, the use of different markers to assess and confirm successful induction of colitis is somewhat inconsistent. This study aimed to investigate the DSS model to improve the preclinical evaluation of new oral drug formulations. The induction of colitis was evaluated based on the disease activity index (DAI) score, colon length, histological tissue evaluation, spleen weight, plasma C-reactive protein, and plasma lipocalin-2. Furthermore, the study investigated how the DSS-induced colitis affected the luminal pH, lipase activity, and concentrations of bile salts, polar lipids, and neutral lipids. For all evaluated parameters, healthy rats were used as a reference. The DAI score, colon length, and histological evaluation of the colon were effective disease indicators in DSS-induced colitis rats, while spleen weight, plasma C-reactive protein, and plasma lipocalin-2 were not. The luminal pH of the colon and bile salt- and neutral lipid concentrations in regions of the small intestine were lower in DSS-induced rats compared to healthy rats. Overall, the colitis model was deemed relevant for investigating ulcerative colitis-specific formulations.

Novel Finding of Urinary Erythropoietin as an Early Biomarker of Cisplatin-Induced Nephrotoxicity.

Cisplatin is a chemotherapeutic drug used to treat a great variety of solid tumors. Its dose is commonly limited by its nephrotoxicity, manifested as acute kidney injury (AKI). Erythropoietin (Epo) is a glycoprotein hormone that regulates the production of red blood cells. This study was performed to evaluate the presence of endogenous Epo in male Wistar rat urine and to analyse changes in urinary Epo levels in response to cisplatin- induced AKI. Dose-dependent studies and time-dependent experiments were performed to evaluate changes in urea nitrogen and creatinine in plasma as well as Epo, neutrophil gelatinase-associated lipocalin (NGAL), alkaline phosphatase (AP) activity, creatinine and total proteins in urine at 2 days post-dosing. Rats received 2, 5 or 10 mg/kg b.w., i.p. of cisplatin. At 5 mg/kg b.w., i.p. cisplatin, significant increases in urinary Epo were detected. Significant increases in urea nitrogen and creatinine in plasma, NGAL, AP, proteins, and Epo were observed in urine from rats that received 10 mg/kg b.w., i.p. of cisplatin. In the time-dependent experiments, rats were injected with a dose of 5 mg/kg b.w., i.p. of cisplatin, and sampling occurred 2, 4, and 14 days post-dosing. In these animals, there were significant increases in urea nitrogen and creatinine in plasma and total proteins, AP activity, Epo, and NGAL in urine on day 4. Urinary Epo was also detected on day 2. Taken together, these findings provide weight of evidence for urinary Epo as a promising early biomarker of cisplatin-induced AKI in male rats.

Values of serum neutrophil gelatinase-associated lipocalin and cystatin C after percutaneous coronary intervention for early diagnosis of contrast-induced nephropathy.

Objective: Serum creatinine (SCr) is not a sensitive and reliable index for the early diagnosis of acute kidney injury caused by contrast-induced nephropathy (CIN). The aim of this study was to explore the values of serum neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C (Cys-C) after percutaneous coronary intervention (PCI) for the early diagnosis of CIN. Methods: Three hundred patients receiving PCI from January 2018 to December 2020 were assigned to a CIN group (n=25) and a non-CIN group (n=275), respectively. SCr, Cys-C and NGAL levels were measured, and their sensitivities for early CIN diagnosis were evaluated by the area under the receiver operating characteristic curve (AUC) values. Results: The NGAL and Cys-C levels of the CIN group began to rise 6 and 12 h after operation, respectively (P<0.05). The CIN group had higher NGAL and Cys-C levels than those of the non-CIN group 12, 24 and 48 h after operation (P<0.05). The AUC values of NGAL, Cys-C and SCr 24 h after operation were 0.885, 0.874 and 0.856, respectively. Conclusion: The serum NGAL and Cys-C levels of patients after PCI reflect the early changes of renal function, which are valuable for early CIN diagnosis.

Relationships of adipocyte-fatty acid binding protein and lipocalin 2 with risk factors and chronic complications in type 2 diabetes and effects of fenofibrate: A fenofibrate Intervention and event lowering in diabetes sub-study.

AIMS: To investigate determinants of circulating levels of adipocyte-fatty acid binding protein (A-FABP) and lipocalin-2 (LCN2), their relationships with cardiovascular disease (CVD) and microvascular events, and effects of fenofibrate in type 2 diabetes (T2D). METHODS: A-FABP and LCN2 were quantified in baseline plasma from 2000 T2D adults in a Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial sub-study and correlates thereof determined. In a subset (n = 200) adipokines were also measured on-trial. RESULTS: Female sex, older age, higher body mass index (BMI), HbA1c, insulin resistance index, triglycerides, plasma creatinine and homocysteine, shorter diabetes duration, and use of oral hypoglycaemic agents alone were independent determinants of higher A-FABP. Higher BMI, fibrinogen and homocysteine, Caucasian race, and lower fasting glucose, HDL-cholesterol, apolipoprotein A-II and estimated glomerular filtration rate were independent predictors of higher LCN2 levels. Baseline A-FABP and LCN2 levels were associated with multiple new CVD and microvascular events over 5-years, though significance was lost after risk factor adjustment. Fenofibrate increased A-FABP but did not change LCN2 levels. CONCLUSIONS: Baseline plasma A-FABP and LCN2 levels were associated with concurrent CVD risk factors, and on-trial chronic complications, likely mediated via traditional risk factors. Fenofibrate increased A-FABP modestly but did not affect LCN2 levels. CLINICAL TRIAL REGISTRATION: ISRCTN 64783481.